A high-precision out-of-plane deformation measurement system and method under non-isolation conditions

Abstract

The application relates to a high-precision out-of-plane deformation measurement system and method under non-isolation conditions, which comprises a laser light source and an optical path, an image high-speed acquisition system and a laser Doppler vibration measurement system. The application utilizes synchronous and continuous measurement of a high-speed camera and a laser Doppler vibration meter, the high-speed camera records a pattern formed by interference of a reference end and an object end, and filters out effective fringe patterns which are less affected by decorrelation; the laser Doppler vibration meter measures rigid body displacement caused by vibration and takes the displacement as a phase shift; a series of fringe patterns with the same initial state and known phase shifts are obtained, which are used for phase calculation before and after object deformation, and high-precision object deformation information is obtained. The application can not only avoid speckle decorrelation phenomenon caused by excessive vibration, but also reduce errors caused by in-plane displacement caused by vibration, and solve the problems of inaccurate phase shift and the inability to distinguish vibration phase and deformation phase.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of optical testing, and particularly relates to a high-precision (nanometer level) out-of-plane deformation measurement system and method under non-vibration isolation conditions. BACKGROUND

[0002] The interference measurement technology combined with the phase shift method is currently recognized as the highest resolution measurement method, and is widely used in the fields of optical element surface detection, micro-deformation measurement, non-destructive testing and the like. However, the measurement resolution will be limited by the background noise. In the measurement process, environmental vibration and atmospheric turbulence will cause unknown phase shift and tilt change of the object, so that the measurement result will also have a large error. The method can usually be used only under the condition of optical laboratory with vibration isolation facilities, and the application scene is limited.

[0003] The optical interference method can be divided into mirror interference and diffuse reflection surface interference. For mirror interference, when there is vibration, the main source of measurement error is the phase shift error caused by unstable fringes. The random phase shift algorithm, instantaneous interference method and synchronous phase shift interference method proposed by researchers can reduce the phase shift error caused by vibration to some extent, and the measurement result can be consistent with that under the vibration isolation condition under certain conditions. However, mirror interference is mainly used for optical surface measurement, and we are more concerned about speckle interference for object deformation measurement. For speckle interference deformation measurement, when there is vibration, there are two problems in addition to the phase shift error. First, the rigid body displacement and object deformation displacement caused by vibration cannot be accurately distinguished. Second, when the displacement caused by vibration is too large, especially the in-plane displacement, the speckle decorrelation phenomenon occurs, which greatly reduces the fringe contrast. Even the shear electronic speckle interferometer, which is a common-path interferometer system insensitive to vibration, cannot avoid this problem. Therefore, it is difficult to build a speckle interferometry system with high-precision measurement characteristics and robustness to vibration interference. Currently, there is no related measurement system reported in the international field. SUMMARY

[0004] The technical problem of the present application is to overcome the shortcomings of the prior art, provide a device and method for object deformation measurement under non-vibration isolation conditions, solve the problem of speckle decorrelation caused by excessive vibration, reduce the error caused by in-plane displacement due to vibration, solve the problem of inaccurate phase shift and the inability to distinguish between vibration phase and deformation phase in a vibration environment, and solve the problem of accurate acquisition of object deformation phase in a vibration environment. The present application can realize high-precision interferometry deformation measurement in a vibration environment, and does not have the phase shift error caused by vibration. Moreover, the calculation process is simple and has high calculation efficiency.

[0005] The technical solution for achieving the object of the present application is as follows:

[0006] In a first aspect, a high-precision out-of-plane deformation measurement system under non-vibration isolation conditions is provided, comprising: a laser light source and optical path, an image high-speed acquisition system, and a laser Doppler vibration measurement system.

[0007] The laser light source and optical path include a He-Ne laser generator generating a stable light source and an optical path built based on the Michelson interference principle.

[0008] In the optical path, the measured object (5) is placed outside the vibration isolation platform (12), and the laser (1), beam expander (2), beam splitter (3), reference mirror (4), and high-speed camera (6) are placed on the vibration isolation platform (12).

[0009] The laser (1) emits a stable point light source, which is expanded into a set of uniform parallel light after passing through the beam expander (2). The parallel light is split into two identical beams by the beam splitter (3), one of which is incident on the measured object (5) and returns along the optical path after diffuse reflection on the surface of the measured object (5) to become a measurement beam. The other is incident on the reference mirror (4) and returns along the optical path after reflection on the surface of the reference mirror (4) to become a reference beam. The reference beam and the measurement beam interfere on the target surface of the high-speed camera (6) to form an interference pattern related to the deformation.

[0010] The image high-speed acquisition system is a high-speed camera (6) for recording laser interference patterns.

[0011] The laser Doppler vibration measurement system (11) is a laser Doppler vibration instrument for measuring the out-of-plane vibration displacement of the measured object (5). The laser Doppler vibration measurement system (11) includes a first laser Doppler vibration instrument (7), a second laser Doppler vibration instrument (8), and a third laser Doppler vibration instrument (9). The first laser Doppler vibration instrument (7), the second laser Doppler vibration instrument (8), and the third laser Doppler vibration instrument (9) are placed on the vibration isolation platform (12) and are not collinear in space. The laser of the first laser Doppler vibration instrument (7), the second laser Doppler vibration instrument (8), and the third laser Doppler vibration instrument (9) is perpendicular to the rigid body of the measured object (5), and the returned laser is frequency demodulated to obtain the out-of-plane displacement of the measurement point on the measured object.

[0012] Further, the high-speed camera (6) is set to high-frequency acquisition according to the amplitude and frequency of the actual ground vibration, with a high frequency of 1000-10000 Hz, to record the high-stripe contrast stripe pattern in the vibration environment.

[0013] Further, the frame rate of the laser Doppler vibration measurement system (11) and the high-speed camera (6) is set to be consistent, and they are collected synchronously.

[0014] Secondly, the present invention provides a high-precision out-of-plane deformation measurement method under non-vibration isolation conditions. It utilizes a high-speed camera (6) and a laser Doppler vibration measurement system (11) to simultaneously and continuously measure and acquire a series of fringe patterns with known phase shifts before and after deformation of the object under test (5). The deformation information of the object under test (5) is further calculated. The implementation steps are as follows:

[0015] Step 1: Calibrate the spatial positions of the high-speed camera (6) and the first laser Doppler vibration meter (7), the second laser Doppler vibration meter (8), and the third laser Doppler vibration meter (9), and define the high-speed camera (6) and the laser Doppler vibration measurement system (11) in the same spatial coordinate system;

[0016] Step 2: The high-speed camera (6) records an interferogram as a reference speckle pattern I0, and the position of the object being measured at that moment is taken as the initial reference position. The reference mirror (4) is adjusted to introduce the spatial carrier frequency.

[0017] Step 3: Set the frame rate of the first laser Doppler vibrometer (7), the second laser Doppler vibrometer (8), the third laser Doppler vibrometer (9), and the high-speed camera (6) to be the same, trigger them synchronously, and record them continuously at high speed during the deformation process of the object under test (5). Among them, the continuously acquired speckle pattern sequence I n Subtracting the reference speckle pattern I0 from the result, a series of related fringe patterns I are obtained. n t The data includes the out-of-plane vibration displacement of three points on the corresponding test object (5). Since the test object is in a vibration environment, the resulting fringe pattern sequence includes fringe patterns with high fringe contrast and small calculation error obtained when the test object is near the initial reference position and no speckle decorrelation phenomenon occurs, as well as fringe patterns with blurred fringe, large calculation error, or even fringe disappearance and incomprehensibility obtained when the test object is far from the initial reference position and speckle decorrelation phenomenon occurs.

[0018] Step 4: Based on the background light intensity and modulation amplitude of the obtained stripe pattern, set the stripe contrast threshold, and select N frames of stripe patterns with high stripe contrast and small calculation error from the stripe patterns before and after deformation according to the stripe contrast threshold, where N≥3.

[0019] Step 5: Treat the displacement caused by vibration as rigid body displacement. Find the data corresponding to the time of the stripe pattern selected in Step 4 in the out-of-plane vibration displacement data of the three points in Step 3. Use this data to fit the out-of-plane vibration displacement of the plane of the measured object (5) at each time. Directly convert the out-of-plane vibration displacement as a phase shift to obtain the phase shift corresponding to the stripe pattern selected in Step 4.

[0020] Step 6, according to the fringe pattern screened out in step 4 and the phase shift corresponding to the fringe pattern obtained in step 5, the phase distribution of the measured object (5) before and after deformation is calculated respectively after filtering and denoising the fringe pattern, and the deformation information of the measured object (5) is obtained.

[0021] Further, the step 5 is specifically implemented as:

[0022] The expression of the corresponding fitting in-plane vibration displacement of the measured object (5) at each time is:

[0023] z t =k1x+k2y+k3,

[0024] Wherein, (x, y) is the plane coordinate of the measured object (5), z t is the out-of-plane vibration displacement of each point on the measured object (5) at time t, k1, k2, k3 are parameters fitted according to three measurement points (x1, y1, z1), (x2, y2, z2), (x3, y3, z3), and the conversion expression of the out-of-plane vibration displacement and the phase shift is:

[0025]

[0026] Wherein, δ n t (x, y) t is the phase shift size of each point on the plane of the measured object (5) at time t, and λ is the wavelength of laser.

[0027] Compared with the prior art, the present application has the following advantages:

[0028] (1) For the traditional electronic speckle interferometry method, a general industrial camera is usually used, when the speckle decorrelation phenomenon caused by vibration occurs, the general industrial camera can only record the interference pattern of blurred fringe or even the disappearance of fringe, so that the calculation cannot be further carried out. In the present application, a high-speed camera is used for collection, when the measured object is on a non-isolation platform and there is vibration, the high-speed camera can record the interference fringe pattern of the measured object at different vibration positions. Since the vibration is reciprocating, as long as the object can return to the equilibrium position and the camera frame rate is sufficient, the interference pattern with high fringe contrast and small calculation error can always be recorded. Selecting these interference patterns for calculation can avoid the problem of speckle decorrelation, and the in-plane displacement of these interference patterns can be ignored, so that the present application can perform high-precision interferometric deformation measurement even in a vibrating environment.

[0029] (2) Traditional phase-shifting interferometry typically uses a phase shifter to introduce phase shift and assumes that the first interferogram has no phase shift. However, phase shifters are often inaccurate, and traditional algorithms for obtaining accurate phase shifts often require complex theoretical calculations. When vibration is present, it cannot be guaranteed that the object before and after deformation has the same initial position, that is, the initial state of the phase related to deformation in the interferogram before and after deformation is not the same, so phase error is inevitable. In this invention, a precise phase shifting device is not required. The rigid body displacement of the measured object caused by vibration is regarded as a phase shift, which can be directly obtained by a laser Doppler vibrometer. Therefore, the phase shift error caused by the inaccuracy of the phase shifter is avoided, the calculation process for solving the accurate phase shift is greatly simplified, and the calculation efficiency is improved. Furthermore, since the laser Doppler vibrometer records continuously during the deformation process, all phase shifts are relative to the same initial point. Therefore, the initial state of the phase related to deformation in all interferograms is consistent, and the vibration phase and deformation phase can be easily separated, thereby reducing the phase error caused by vibration and realizing high-precision interferometric deformation measurement in a vibration environment.

[0030] (3) The optical path is simple to set up and easy to operate. It can be effectively applied to deformation measurement under complex vibration environment, creating new possibilities for the interferometric method in practical engineering applications. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the optical path structure of the speckle interferometer device for measuring object deformation under non-vibration isolation conditions according to the present invention;

[0032] Figure 2 This is a schematic diagram of the plane of the object being measured in an embodiment of the present invention;

[0033] Figure 3 This is a deformation phase distribution diagram calculated using traditional methods when the tested object is placed on a vibration isolation platform in an embodiment of the present invention.

[0034] Figure 4 This is a deformation phase distribution diagram calculated using the present invention when the object under test is not placed on a vibration isolation platform in an embodiment of the present invention.

[0035] Figure 5 The diagram shows the residual error of two schemes in the embodiments of the present invention. Detailed Implementation

[0036] The invention will now be described in further detail with reference to the embodiments.

[0037] like Figure 1 As shown, an embodiment of the present invention provides a high-precision out-of-plane deformation measurement device under non-vibration isolation conditions, comprising: a laser source and optical path, a high-speed image acquisition system, and a laser Doppler vibration measurement system.

[0038] The laser light source and light path are a Michelson speckle interferometry system 10, a He-Ne laser emits a stable point light source, after passing through a beam expander 2, the point light source is expanded into a set of uniform parallel light, the parallel light is split into two identical beams by a beam splitter 3, one of the beams is irradiated on a measured object 5, and after being diffusely reflected on the surface of the measured object 5, returns along the light path to become a measurement beam; the other beam is irradiated on a reference plane mirror 4, and after being reflected on the surface of the reference plane mirror 4, also returns along the light path to become a reference beam. The reference beam and the measurement beam interfere on the target surface of a high-speed camera 6 to form an interference pattern related to the deformation amount.

[0039] Further, the measured object 5 is placed outside the vibration isolation platform 12.

[0040] Further, the laser 1, the beam expander 2, the beam splitter 3, the reference mirror 4 and the high-speed camera 6 are placed on the vibration isolation platform 12.

[0041] The image high-speed acquisition system is the high-speed camera 6.

[0042] The laser Doppler vibrometer system 11 comprises a first laser Doppler vibrometer 7, a second laser Doppler vibrometer 8 and a third laser Doppler vibrometer 9.

[0043] Further, the first laser Doppler vibrometer 7, the second laser Doppler vibrometer 8 and the third laser Doppler vibrometer 9 are placed on the vibration isolation platform 12 and are non-collinear in space; the laser of the first laser Doppler vibrometer 7, the second laser Doppler vibrometer 8 and the third laser Doppler vibrometer 9 is vertically incident to the rigid body part of the measured object 5, and the returned laser is frequency demodulated to obtain the out-of-plane displacement of the measurement point on the measured object.

[0044] Further, the high-speed camera 6 is set to high-frequency acquisition according to the amplitude and frequency of the actual ground vibration, the high frequency is between 1000-10000 Hz, so as to record the high-stripe contrast stripe pattern in the vibration environment.

[0045] Further, the frame rate of the laser Doppler vibrometer system 11 and the high-speed camera 6 is set to be consistent, and the acquisition is performed synchronously.

[0046] The high-precision out-of-plane deformation measurement method under non-vibration isolation conditions comprises the following steps:

[0047] Step 1, before the deformation measurement experiment, the spatial positions of the high-speed camera 6 and the first laser Doppler vibrometer 7, the second laser Doppler vibrometer 8 and the third laser Doppler vibrometer 9 are calibrated, and the high-speed camera 6 and the laser Doppler vibrometer system 11 are defined in the same spatial coordinate system.

[0048] Step 2, record the next interference pattern by high-speed camera 6 as reference speckle pattern I0, and take the position of the measured object at this moment as the initial reference position. In order to facilitate observation and calculation, adjust the reference mirror 4 to introduce a spatial carrier frequency.

[0049] Step 3, select the appropriate frame rate according to the actual vibration frequency and amplitude, and set the frame rates of the first laser Doppler vibrometer 7, the second laser Doppler vibrometer 8, the third laser Doppler vibrometer 9 and the high-speed camera 6 to be the same, and trigger them synchronously. Record the high-speed continuous speckle pattern sequence I n I0, and finally obtain a series of correlation fringe pattern sequences I n t and the corresponding out-of-plane vibration displacement data of three points on the measured object. Under the condition of vibration, the speckle interference system is particularly prone to speckle decorrelation. Some fringe patterns have poor fringe contrast due to the influence of speckle decorrelation (especially the fringe patterns with large in-plane displacement). However, since the vibration is reciprocating, the fringe patterns near the initial reference position have ideal fringe contrast, and the phase of the fringe pattern at this time is less affected by the in-plane displacement. When the frame rate of the high-speed camera is large enough, these fringe patterns that can be used for calculation can be recorded. Therefore, the obtained fringe pattern sequence I n t contains both fringe patterns with high fringe contrast and small calculation error obtained when the measured object is near the initial reference position and speckle decorrelation does not occur, and fringe patterns with blurred fringe, large calculation error, even fringe disappearance and no calculation can be performed obtained when the measured object is far from the initial reference position and speckle decorrelation occurs;

[0050] Step 4, set the fringe contrast threshold according to the actual background light intensity and modulation amplitude of the obtained fringe pattern, and select N frames (N≥3) of fringe patterns with high fringe contrast and small calculation error from the fringe patterns before and after deformation according to the fringe contrast threshold (it is considered that the object does not deform in a very short time, and the phase change of N frames of fringe patterns is only caused by vibration).

[0051] Step 5, consider the displacement caused by vibration as rigid body displacement. Since the high-speed camera and the laser Doppler vibrometer are recorded synchronously, the out-of-plane vibration displacement data at the corresponding time of the selected fringe patterns in step 4 can be found in the out-of-plane vibration displacement data of the three points in step 3. Use this data to fit the out-of-plane vibration displacement of the measured object 5 plane at the corresponding time, and directly use the out-of-plane vibration displacement as the phase shift to obtain the phase shift corresponding to the selected fringe patterns in step 4. The expression of the fitted out-of-plane vibration displacement of the measured object plane at the corresponding time is:

[0052] zt = k1x + k2y + k3,

[0053] where (x, y) is the measured object plane coordinates, z t is the measured object on each point of the time t out-of-plane vibration displacement, k1, k2, k3 is the fitting of the three measurement points (x1, y1, z1), (x2, y2, z2), (x3, y3, z3) obtained parameters. The size of the phase shift at each time can be converted to get:

[0054]

[0055] where δ n t (x, y) is the measured object plane at each point of the time t phase shift size, λ is the wavelength of the laser.

[0056] Step 6, according to step 4 selected from the fringe pattern and according to step 5 obtained from the fringe pattern corresponding to the phase shift, after the fringe pattern filtering denoising, using the least square solution phase method respectively calculated before and after the measured object deformation phase distribution, further obtain the deformation information of the measured object. Specifically as follows:

[0057] The intensity of the fringe pattern can be expressed as:

[0058]

[0059] where (x, y) is the measured object plane image coordinates, A (x, y) and B (x, y) are the background intensity and interference intensity modulation item of the interference pattern, is the deformation related to the measured phase, for this embodiment, that is, the phase distribution before and after the deformation of the measured object δ n t (x, y) is the phase shift at time t.

[0060] When N ≥ 3 and the fringe pattern intensity I n t (x, y) and the phase shift δ n t (x, y) is known, can be obtained by the least square solution phase method, the deformation information is characterized by . Wherein, because the phase of the measured object before and after the deformation the initial state is the same, the deformation information of the measured object is obtained there is no vibration phase error, with high accuracy.

[0061] Embodiment

[0062] In this embodiment, the wavelength of the laser used is 632.8 nm, the imaging device used is a high-speed camera from Richvision, model X213_ISP, with a pixel resolution of 1280*1024 pixels and a unit pixel size of 14.6 um, and the RIO size is set to 180*180 pixels, the sampling rate is 1000 Hz, and 10 frames of fringe patterns are selected within 0.1 s before and after deformation for calculation. The laser Doppler vibration measurement system used is FNV-R4D-VD1 from Holobright, with a measurement accuracy of nanometer level, and the distribution of the laser points of the three laser Doppler vibration meters is as shown in Figure 2 The sampling rate is the same as that of the high-speed camera.

[0063] In order to verify the high-precision out-of-plane deformation measurement method under non-isolation conditions, a comparative test was conducted. The same central loading was performed on the measured object, and the deformation of the measured object was calculated using the traditional four-step phase shift method and the high-precision out-of-plane deformation measurement method under non-isolation conditions, respectively, when the measured object was placed on the isolation table and outside the isolation table, and the results were compared to obtain the residual error.

[0064] Figure 3 is the deformation phase pattern calculated using the traditional method under isolation conditions, where the horizontal and vertical coordinates are in pixels, and the height coordinate is in wavelength (λ), and the PV value of the calculated deformation is 0.4496λ, Figure 4 is the deformation phase pattern calculated using the high-precision out-of-plane deformation measurement method under non-isolation conditions under the condition of severe vibration of the object, and the units are the same as those of Figure 3 , and its PV value is 0.4594λ. From the numerical results and phase distribution of Figure 3 and Figure 4 , the deformation results calculated by the two methods are basically consistent, Figure 5 is the calculation error graph of the two methods, and the units are the same as those of Figure 3 , Figure 4 The PV value and RMS of the error are 0.1112λ and 0.0116λ, respectively. The comparative test shows that the method has good robustness and can perform high-precision speckle interferometric deformation measurement under non-isolation conditions, effectively solving the measurement error caused by environmental vibration and air flow disturbance, which cannot be achieved by the traditional time shift and spatial carrier method.

[0065] The above embodiments are provided only for the purpose of describing the present application, and are not intended to limit the scope of the present application. The scope of the present application is defined by the appended claims. Various equivalent substitutions and modifications made without departing from the spirit and principles of the present application should be encompassed within the scope of the present application.

Claims

1. A high-precision out-of-plane deformation measurement system under non-isolation conditions, characterized in that, Comprise: Laser light source and light path, image high-speed acquisition system and laser Doppler vibration measurement system; The laser light source and light path, a He-Ne laser generator generating stable light source and an optical path based on Michelson interference principle; In the optical path, the measured object (5) is placed outside the vibration isolation platform (12), and the laser (1), beam expander (2), optical splitter (3), reference mirror (4) and high-speed camera (6) are placed on the vibration isolation platform (12); The laser (1) emits a stable point light source, which is expanded into a group of uniform parallel light after the beam expander (2), and the parallel light is split into two identical beams by the optical splitter (3), one of which is irradiated on the measured object (5), and the other is irradiated on the reference mirror (4), which is reflected on the surface of the reference mirror (4) and returns along the light path to become the reference light beam, and the reference light beam and the measurement light beam interfere on the target surface of the high-speed camera (6) to form an interference pattern related to the deformation; The image high-speed acquisition system is a high-speed camera (6) for recording laser interference patterns; The laser Doppler vibration measurement system (11) is a laser Doppler vibration instrument for measuring the out-of-plane vibration displacement of the measured object (5), which comprises a first laser Doppler vibration instrument (7), a second laser Doppler vibration instrument (8) and a third laser Doppler vibration instrument (9); The first laser Doppler vibration instrument (7), the second laser Doppler vibration instrument (8) and the third laser Doppler vibration instrument (9) are placed on the vibration isolation platform (12) and are not collinear in space; The laser of the first laser Doppler vibration instrument (7), the second laser Doppler vibration instrument (8) and the third laser Doppler vibration instrument (9) is perpendicular to the rigid body of the measured object (5), and the returned laser is frequency demodulated to obtain the out-of-plane displacement of the measured point on the measured object.

2. The high-precision out-of-plane deformation measurement system under non-isolation conditions according to claim 1, characterized in that: The high-speed camera (6) is set to high-frequency acquisition according to the amplitude and frequency of the actual ground vibration, and the high frequency is between 1000-10000Hz, so as to record the high-stripe contrast stripe pattern in the vibration environment.

3. The high-precision out-of-plane deformation measurement system under non-isolation conditions according to claim 1, characterized in that: The frame rate of the laser Doppler vibration measurement system (11) and the high-speed camera (6) is set to be consistent, and the acquisition is carried out synchronously.

4. A high-precision out-of-plane deformation measurement method under non-isolation conditions, characterized in that: The high-speed camera (6) and the laser Doppler vibration measurement system (11) are used for synchronous continuous measurement, a series of known phase shift stripe patterns of the measured object (5) before and after deformation are obtained, and the deformation information of the measured object (5) is further calculated, and the steps are as follows: Step 1, calibrate the spatial positions of the high-speed camera (6) and the first laser Doppler vibration instrument (7), the second laser Doppler vibration instrument (8) and the third laser Doppler vibration instrument (9), and define the high-speed camera (6) and the laser Doppler vibration system (11) in the same spatial coordinate system; Step 2, record one interference pattern as reference speckle pattern I0 by the high-speed camera (6), and take the position of the measured object at this moment as the initial reference position, and adjust the reference mirror (4) to introduce the spatial carrier frequency; Step 3, set the frame rate of the first laser Doppler vibrometer (7), the second laser Doppler vibrometer (8), the third laser Doppler vibrometer (9) and the high-speed camera (6) to be the same, trigger synchronously, and record continuously during the deformation of the measured object (5), wherein the sequence of speckle patterns I n is obtained by subtracting the reference speckle pattern I0from the continuously collected speckle pattern sequence I n t and the corresponding out-of-plane vibration displacement data of three points on the measured object (5); wherein since the measured object is in a vibrating environment, the obtained sequence of fringe patterns contains both fringe patterns with high fringe contrast, small calculation error when the measured object is near the initial reference position and no speckle decorrelation occurs, and fringe patterns with blurred fringes, large calculation error or even no fringes, which cannot be calculated when the measured object is far from the initial reference position and speckle decorrelation occurs. Step 4, according to the background light intensity and the modulation amplitude of the actually obtained fringe pattern, setting the fringe contrast threshold, and according to the fringe contrast threshold, screening out N frames of fringe patterns with high fringe contrast and small calculation error from the fringe patterns before and after deformation respectively, wherein N≥3; Step 5, regarding the displacement caused by vibration as the rigid body displacement, finding the data corresponding to the time of the screened fringe pattern in step 4 from the out-of-plane vibration displacement data of the three points in step 3, fitting the out-of-plane vibration displacement of the measured object (5) plane at the corresponding time using the data, directly converting the out-of-plane vibration displacement as the phase shift to obtain the phase shift corresponding to the screened fringe pattern in step 4; Step 6, according to the fringe pattern screened in step 4 and the phase shift corresponding to the fringe pattern obtained in step 5, calculating the phase distribution of the measured object (5) before and after deformation respectively after filtering and denoising the fringe pattern, and obtaining the deformation information of the measured object (5).

5. The high-precision out-of-plane deformation measurement method under non-isolation conditions according to claim 4, characterized in that, The step 5 is specifically implemented as: The fitted out-of-plane vibration displacement expression of the measured object (5) plane at the corresponding time is: z t = k1x + k2y + k3, where (x, y) is the planar coordinate of the measured object (5), z t is the out-of-plane vibration displacement of each point on the measured object (5) at time t, k1, k2, k3 are parameters fitted according to three measurement points (x1, y1, z1), (x2, y2, z2), (x3, y3, z3), and the conversion expression of the out-of-plane vibration displacement and the phase shift is: where δ n t (x, y) is the phase shift of each point on the plane of the measured object (5) at time t, and λ is the laser wavelength.

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